1. Field of the Invention
The present invention relates to an image processing apparatus for determining, extracting and correcting defective pixel signals from defective pixels in an array of pixels in a sensor.
2. Description of the Related Art
Hitherto, the following method has been employed for detecting and correcting defective pixel signals from defective pixels within a sensor array. A detected defective pixel signal pattern is stored as a binary image, as shown in FIG. 1. In correcting an image taken of a subject, the stored defective pixel signal pattern is read, and the individual pixel signals are sequentially searched. If there is any defective pixel signal, it is corrected by, for example, replacing it with an average value of the surrounding pixel signals.
If a defective pixel signal pattern is not formed, coordinate values of the individual defective pixels are stored, and corrections are performed on pixel signals having the corresponding coordinates of a subject image in a manner similar to the above method.
However, the ratio of defective pixels to normal pixels within a sensor is very small, and in searching a defective pixel pattern, most of the pixels are merely skipped. Thus, searching the whole image takes time and is wasteful.
According to the technique using coordinate values of defective pixels in the sensor, a given defective pixel signal cannot be accurately corrected if there is another defective pixel near the given defective pixel in the sensor.